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netsurf/render/css.c

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/**
* $Id: css.c,v 1.13 2003/02/09 12:58:15 bursa Exp $
*/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "netsurf/render/css.h"
#include "netsurf/utils/utils.h"
/**
* internal structures
*/
struct rule {
struct css_selector * selector;
unsigned int selectors;
struct css_style * style;
struct rule * next;
};
struct decl {
unsigned long score;
struct rule * rule;
};
#define HASH_SIZE 1
struct css_stylesheet {
struct rule * hash[HASH_SIZE];
};
static int parse_length(struct css_length * const length, const char *s);
static colour parse_colour(const char *s);
static void parse_background_color(struct css_style * const style, const char * const value);
static void parse_clear(struct css_style * const style, const char * const value);
static void parse_color(struct css_style * const style, const char * const value);
static void parse_display(struct css_style * const style, const char * const value);
static void parse_float(struct css_style * const style, const char * const value);
static void parse_font_size(struct css_style * const style, const char * const value);
static void parse_height(struct css_style * const style, const char * const value);
static void parse_text_align(struct css_style * const style, const char * const value);
static void parse_width(struct css_style * const style, const char * const value);
static void parse_selector(struct css_selector * sel, char * const str);
static unsigned int hash_str(const char * str);
static int seleq(const struct css_selector * const s1, const struct css_selector * const s2);
static unsigned long selmatch(const struct css_selector * const s, const struct css_selector * const sr);
static struct rule * find_rule(struct css_stylesheet * stylesheet,
struct css_selector * selector, unsigned int selectors);
static int cmpdecl(const struct decl * d0, const struct decl * d1);
static void update_style(struct css_stylesheet * stylesheet, struct css_selector * selector,
unsigned int selectors, char * str);
static void dump_length(const struct css_length * const length);
static void dump_selector(const struct css_selector * const sel);
static void dump_rule(const struct rule * rule);
const struct css_style css_base_style = {
0xffffff,
CSS_CLEAR_NONE,
0x000000,
CSS_DISPLAY_BLOCK,
CSS_FLOAT_NONE,
{ CSS_FONT_SIZE_LENGTH, { { 12, CSS_UNIT_PT } } },
CSS_FONT_WEIGHT_NORMAL,
CSS_FONT_STYLE_NORMAL,
{ CSS_HEIGHT_AUTO, { 1, CSS_UNIT_EM } },
{ CSS_LINE_HEIGHT_ABSOLUTE, { 1.2 } },
CSS_TEXT_ALIGN_LEFT,
{ CSS_WIDTH_AUTO, { { 1, CSS_UNIT_EM } } }
};
const struct css_style css_empty_style = {
CSS_COLOR_INHERIT,
CSS_CLEAR_INHERIT,
CSS_COLOR_INHERIT,
CSS_DISPLAY_INHERIT,
CSS_FLOAT_INHERIT,
{ CSS_FONT_SIZE_INHERIT, { { 1, CSS_UNIT_EM } } },
CSS_FONT_WEIGHT_INHERIT,
CSS_FONT_STYLE_INHERIT,
{ CSS_HEIGHT_AUTO, { 1, CSS_UNIT_EM } },
{ CSS_LINE_HEIGHT_INHERIT, { 1.2 } },
CSS_TEXT_ALIGN_INHERIT,
{ CSS_WIDTH_INHERIT, { { 1, CSS_UNIT_EM } } }
};
const struct css_style css_blank_style = {
TRANSPARENT,
CSS_CLEAR_NONE,
CSS_COLOR_INHERIT,
CSS_DISPLAY_INLINE,
CSS_FLOAT_NONE,
{ CSS_FONT_SIZE_INHERIT, { { 1, CSS_UNIT_EM } } },
CSS_FONT_WEIGHT_INHERIT,
CSS_FONT_STYLE_INHERIT,
{ CSS_HEIGHT_AUTO, { 1, CSS_UNIT_EM } },
{ CSS_LINE_HEIGHT_INHERIT, { 1.2 } },
CSS_TEXT_ALIGN_INHERIT,
{ CSS_WIDTH_AUTO, { { 1, CSS_UNIT_EM } } }
};
/**
* property parsers
*/
static int parse_length(struct css_length * const length, const char *s)
{
length->unit = css_unit_parse(s + strspn(s, "0123456789+-."));
if (length->unit == CSS_UNIT_UNKNOWN) return 1;
length->value = atof(s);
return 0;
}
static colour parse_colour(const char *s)
{
int len = strlen(s);
colour c = TRANSPARENT;
unsigned int r, g, b;
if (s[0] == '#' && len == 4) {
if (sscanf(s + 1, "%1x%1x%1x", &r, &g, &b) == 3)
c = (b << 20) | (b << 16) | (g << 12) | (g << 8) | (r << 4) | r;
} else if (s[0] == '#' && len == 7) {
if (sscanf(s + 1, "%2x%2x%2x", &r, &g, &b) == 3)
c = (b << 16) | (g << 8) | r;
} else if (sscanf(s, "rgb(%u, %u, %u)", &r, &g, &b) == 3) {
c = (b << 16) | (g << 8) | r;
} else if (sscanf(s, "rgb(%u%%, %u%%, %u%%)", &r, &g, &b) == 3) {
c = ((int) (b * 2.55) << 16) | ((int) (g * 2.55) << 8) | (int) (r * 2.55);
}
return c;
}
static void parse_background_color(struct css_style * const style, const char * const value)
{
if (strcmp(value, "transparent") == 0) {
style->background_color = TRANSPARENT;
} else {
style->background_color = parse_colour(value);
}
}
static void parse_clear(struct css_style * const style, const char * const value)
{
style->clear = css_clear_parse(value);
}
static void parse_color(struct css_style * const style, const char * const value)
{
style->color = parse_colour(value);
}
static void parse_display(struct css_style * const style, const char * const value)
{
style->display = css_display_parse(value);
}
static void parse_float(struct css_style * const style, const char * const value)
{
style->float_ = css_float_parse(value);
}
static void parse_font_weight(struct css_style * const style, const char * const value)
{
style->font_weight = css_font_weight_parse(value);
}
static void parse_font_style(struct css_style * const style, const char * const value)
{
style->font_style = css_font_style_parse(value);
}
#define SIZE_FACTOR 1.2
static struct font_size {
const char * keyword;
float size;
} const font_size[] = {
{ "xx-small", 1.0 / (SIZE_FACTOR * SIZE_FACTOR * SIZE_FACTOR) },
{ "x-small", 1.0 / (SIZE_FACTOR * SIZE_FACTOR) },
{ "small", 1.0 / SIZE_FACTOR },
{ "medium", 1.0 },
{ "large", 1.0 * SIZE_FACTOR },
{ "x-large", 1.0 * SIZE_FACTOR * SIZE_FACTOR },
{ "xx-large", 1.0 * SIZE_FACTOR * SIZE_FACTOR * SIZE_FACTOR }
};
static void parse_font_size(struct css_style * const style, const char * const value)
{
unsigned int i;
for (i = 0; i < sizeof(font_size) / sizeof(struct font_size); i++) {
if (strcmp(value, font_size[i].keyword) == 0) {
style->font_size.size = CSS_FONT_SIZE_LENGTH;
style->font_size.value.length.unit = CSS_UNIT_PT;
style->font_size.value.length.value = font_size[i].size * 12;
return;
}
}
if (strcmp(value, "larger") == 0) {
style->font_size.size = CSS_FONT_SIZE_PERCENT;
style->font_size.value.percent = SIZE_FACTOR * 100;
} else if (strcmp(value, "smaller") == 0) {
style->font_size.size = CSS_FONT_SIZE_PERCENT;
style->font_size.value.percent = 1 / SIZE_FACTOR * 100;
} else if (strrchr(value, '%')) {
style->font_size.size = CSS_FONT_SIZE_PERCENT;
style->font_size.value.percent = atof(value);
} else if (parse_length(&style->font_size.value.length, value) == 0) {
style->font_size.size = CSS_FONT_SIZE_LENGTH;
}
}
static void parse_height(struct css_style * const style, const char * const value)
{
if (strcmp(value, "auto") == 0)
style->height.height = CSS_HEIGHT_AUTO;
else if (parse_length(&style->height.length, value) == 0)
style->height.height = CSS_HEIGHT_LENGTH;
}
static void parse_line_height(struct css_style * const style, const char * const value)
{
if (strcmp(value, "normal") == 0) {
style->line_height.size = CSS_LINE_HEIGHT_ABSOLUTE;
style->line_height.value.absolute = 1.0;
} else if (strrchr(value, '%')) {
style->line_height.size = CSS_LINE_HEIGHT_PERCENT;
style->line_height.value.percent = atof(value);
} else if (parse_length(&style->line_height.value.length, value) == 0) {
style->line_height.size = CSS_LINE_HEIGHT_LENGTH;
}
}
static void parse_text_align(struct css_style * const style, const char * const value)
{
style->text_align = css_text_align_parse(value);
}
static void parse_width(struct css_style * const style, const char * const value)
{
if (strcmp(value, "auto") == 0)
style->width.width = CSS_WIDTH_AUTO;
else if (strrchr(value, '%')) {
style->width.width = CSS_WIDTH_PERCENT;
style->width.value.percent = atof(value);
} else if (parse_length(&style->width.value.length, value) == 0)
style->width.width = CSS_WIDTH_LENGTH;
}
static struct property {
const char * const name;
void (*parse) (struct css_style * const s, const char * const value);
} const property[] = {
{ "background-color", parse_background_color },
{ "clear", parse_clear },
{ "color", parse_color },
{ "display", parse_display },
{ "float", parse_float },
{ "font-weight", parse_font_weight },
{ "font-size", parse_font_size },
{ "font-style", parse_font_style },
{ "height", parse_height },
{ "line-height", parse_line_height },
{ "text-align", parse_text_align },
{ "width", parse_width },
};
/**
* parse a property list
*/
void css_parse_property_list(struct css_style * style, char * str)
{
char * end;
for (; str != 0; str = end) {
char * prop;
char * value;
unsigned int i;
if ((end = strchr(str, ';')) != 0) {
*end = 0;
end++;
}
if ((value = strchr(str, ':')) == 0)
continue;
*value = 0;
value++;
prop = strip(str);
value = strip(value);
/*fprintf(stderr, "css_parse: '%s' => '%s'\n", prop, value);*/
for (i = 0; i < sizeof(property) / sizeof(struct property); i++) {
if (strcmp(prop, property[i].name) == 0) {
property[i].parse(style, value);
break;
}
}
}
}
/**
* selectors
*/
static void parse_selector(struct css_selector * sel, char * const str)
{
char * dot = strchr(str, '.');
char * hash = strchr(str, '#');
if ((dot == 0) && (hash == 0)) {
sel->element = xstrdup(str);
sel->class = sel->id = 0;
} else if (dot != 0) {
*dot = 0;
sel->element = xstrdup(str);
sel->class = xstrdup(dot + 1);
sel->id = 0;
} else if (hash != 0) {
*hash = 0;
sel->element = xstrdup(str);
sel->class = 0;
sel->id = xstrdup(hash + 1);
}
}
/**
* stylesheet structure
*/
static unsigned int hash_str(const char * str)
{
unsigned int s = 0;
for (; *str != 0; str++)
s += *str;
return s % HASH_SIZE;
}
static int seleq(const struct css_selector * const s1, const struct css_selector * const s2)
{
return strcmp(s1->element, s2->element) == 0 &&
((s1->class == 0 && s2->class == 0) ||
(s1->class != 0 && s2->class != 0 && strcmp(s1->class, s2->class) == 0)) &&
((s1->id == 0 && s2->id == 0) ||
(s1->id != 0 && s2->id != 0 && strcmp(s1->id, s2->id) == 0));
}
static unsigned long selmatch(const struct css_selector * const s, const struct css_selector * const sr)
{
unsigned int c;
if (sr->element[0] != 0 && strcmp(s->element, sr->element) != 0) return 0;
c = s->element[0] == 0 ? 0 : 1;
if (sr->class != 0) {
if (s->class != 0 && strcmp(s->class, sr->class) == 0) return 0x100 + c;
return 0;
}
if (sr->id != 0) {
if (s->id != 0 && strcmp(s->id, sr->id) == 0) return 0x10000 + c;
return 0;
}
return 1;
}
struct css_stylesheet * css_new_stylesheet(void)
{
struct css_stylesheet * stylesheet = xcalloc(1, sizeof(struct css_stylesheet));
return stylesheet;
}
static struct rule * find_rule(struct css_stylesheet * stylesheet,
struct css_selector * selector, unsigned int selectors)
{
struct rule * rule;
for (rule = stylesheet->hash[hash_str(selector[selectors - 1].element)];
rule != 0; rule = rule->next) {
unsigned int i;
if (selectors != rule->selectors)
continue;
/* inv: selector[0..i) == rule->selector[0..i) */
for (i = 0; i != selectors && seleq(&selector[i], &rule->selector[i]); i++)
;
if (i == selectors)
return rule;
}
return 0;
}
static int cmpdecl(const struct decl * d0, const struct decl * d1)
{
if (d0->score < d1->score) return -1;
else if (d0->score == d1->score) return 0;
return 1;
}
void css_get_style(struct css_stylesheet * stylesheet, struct css_selector * selector,
unsigned int selectors, struct css_style * style)
{
struct rule * rule;
struct decl * decl = xcalloc(0, sizeof(struct decl));
unsigned int d, decls = 0;
/* fprintf(stderr, "css_get_style: "); */
/* for (d = 0; d < selectors; d++) dump_selector(&selector[d]); */
/* fprintf(stderr, "\n"); */
for (rule = stylesheet->hash[hash_str(selector[selectors - 1].element)];
rule != 0; rule = rule->next) {
unsigned int i = selectors - 1;
unsigned int j;
unsigned int score, s;
/* for (d = 0; d < rule->selectors; d++) dump_selector(&rule->selector[d]); */
if ((score = selmatch(&selector[i], &rule->selector[rule->selectors - 1])) == 0) {
/* fprintf(stderr, " last selector match fails\n"); */
continue;
}
if (selectors < rule->selectors) {
/* fprintf(stderr, " less selectors than in rule\n"); */
continue;
}
for (j = rule->selectors - 1; j != 0; j--) {
for (; i != 0 && (s = selmatch(&selector[i - 1], &rule->selector[j - 1])) == 0; i--)
;
if (i == 0)
break;
score += s;
}
if (j == 0) {
/* fprintf(stderr, " match\n"); */
decl = xrealloc(decl, (decls + 1) * sizeof(struct decl));
decl[decls].score = score;
decl[decls].rule = rule;
decls++;
} else {
/* fprintf(stderr, " some selector match fails\n"); */
}
}
if (decls == 0) {
css_cascade(style, &css_blank_style);
} else {
qsort(decl, decls, sizeof(struct decl), (int (*) (const void *, const void *)) cmpdecl);
for (d = 0; d < decls; d++) {
/* fprintf(stderr, "%i: 0x%lx\n", d, decl[d].score); */
/* dump_rule(decl[d].rule);*/
css_cascade(style, decl[d].rule->style);
}
}
}
static void update_style(struct css_stylesheet * stylesheet, struct css_selector * selector,
unsigned int selectors, char * str)
{
struct rule * rule = find_rule(stylesheet, selector, selectors);
if (rule == 0) {
unsigned int h = hash_str(selector[selectors - 1].element);
/*fprintf(stderr, "update_style: not present - adding\n");*/
rule = xcalloc(1, sizeof(struct rule));
rule->selector = selector;
rule->selectors = selectors;
rule->style = xcalloc(1, sizeof(struct css_style));
memcpy(rule->style, &css_blank_style, sizeof(struct css_style));
css_parse_property_list(rule->style, str);
rule->next = stylesheet->hash[h];
stylesheet->hash[h] = rule;
} else {
/*fprintf(stderr, "update_style: already present - updating\n");*/
css_parse_property_list(rule->style, str);
free(selector);
}
}
/**
* parse an entire css file or block
*/
void css_parse_stylesheet(struct css_stylesheet * stylesheet, char * str)
{
/* overwrite comments with spaces */
char * copen = strstr(str, "/*");
while (copen != 0) {
char * cclose = strstr(copen + 2, "*/");
if (cclose == 0) { *copen = 0; break; }
memset(copen, ' ', (size_t) (cclose - copen + 2));
copen = strstr(cclose + 2, "/*");
}
while (*str != 0) {
char * open = strchr(str, '{');
char * close = strchr(str, '}');
char * sels_str;
char * comma;
if ((open == 0) || (close == 0)) break;
*open = 0; *close = 0;
sels_str = strip(str);
do {
char * sel_str;
char * space;
char * style_str;
unsigned int selectors = 0;
struct css_selector * selector = xcalloc(0, sizeof(struct css_selector));
comma = strchr(sels_str, ',');
if (comma != 0) *comma = 0;
sel_str = strip(sels_str);
/*fprintf(stderr, "css_parse_stylesheet: %s\n", sel_str);*/
do {
space = strchr(sel_str, ' ');
if (space != 0) *space = 0;
selector = xrealloc(selector, sizeof(struct css_selector) * (selectors + 1));
parse_selector(&selector[selectors++], sel_str);
if (space != 0) sel_str = strip(space + 1);
} while (space != 0);
style_str = xstrdup(open + 1);
update_style(stylesheet, selector, selectors, style_str);
free(style_str);
if (comma != 0) sels_str = strip(comma + 1);
} while (comma != 0);
str = close + 1;
}
}
/**
* dump a style
*/
static void dump_length(const struct css_length * const length)
{
fprintf(stderr, "%g%s", length->value,
css_unit_name[length->unit]);
}
void css_dump_style(const struct css_style * const style)
{
fprintf(stderr, "{ ");
fprintf(stderr, "background-color: #%lx; ", style->background_color);
fprintf(stderr, "clear: %s; ", css_clear_name[style->clear]);
fprintf(stderr, "color: #%lx; ", style->color);
fprintf(stderr, "display: %s; ", css_display_name[style->display]);
fprintf(stderr, "float: %s; ", css_float_name[style->float_]);
fprintf(stderr, "font-size: ");
switch (style->font_size.size) {
case CSS_FONT_SIZE_ABSOLUTE: fprintf(stderr, "[%g]", style->font_size.value.absolute); break;
case CSS_FONT_SIZE_LENGTH: dump_length(&style->font_size.value.length); break;
case CSS_FONT_SIZE_PERCENT: fprintf(stderr, "%g%%", style->font_size.value.percent); break;
case CSS_FONT_SIZE_INHERIT: fprintf(stderr, "inherit"); break;
default: fprintf(stderr, "UNKNOWN"); break;
}
fprintf(stderr, "; ");
fprintf(stderr, "height: ");
switch (style->height.height) {
case CSS_HEIGHT_AUTO: fprintf(stderr, "auto"); break;
case CSS_HEIGHT_LENGTH: dump_length(&style->height.length); break;
default: fprintf(stderr, "UNKNOWN"); break;
}
fprintf(stderr, "; ");
fprintf(stderr, "line-height: ");
switch (style->line_height.size) {
case CSS_LINE_HEIGHT_ABSOLUTE: fprintf(stderr, "[%g]", style->line_height.value.absolute); break;
case CSS_LINE_HEIGHT_LENGTH: dump_length(&style->line_height.value.length); break;
case CSS_LINE_HEIGHT_PERCENT: fprintf(stderr, "%g%%", style->line_height.value.percent); break;
case CSS_LINE_HEIGHT_INHERIT: fprintf(stderr, "inherit"); break;
default: fprintf(stderr, "UNKNOWN"); break;
}
fprintf(stderr, "; ");
fprintf(stderr, "text-align: %s; ", css_text_align_name[style->text_align]);
fprintf(stderr, "width: ");
switch (style->width.width) {
case CSS_WIDTH_AUTO: fprintf(stderr, "auto"); break;
case CSS_WIDTH_LENGTH: dump_length(&style->width.value.length); break;
case CSS_WIDTH_PERCENT: fprintf(stderr, "%g%%", style->width.value.percent); break;
default: fprintf(stderr, "UNKNOWN"); break;
}
fprintf(stderr, "; ");
fprintf(stderr, "}");
}
static void dump_selector(const struct css_selector * const sel)
{
if (sel->class != 0)
fprintf(stderr, "'%s'.'%s' ", sel->element, sel->class);
else if (sel->id != 0)
fprintf(stderr, "'%s'#'%s' ", sel->element, sel->id);
else
fprintf(stderr, "'%s' ", sel->element);
}
static void dump_rule(const struct rule * rule)
{
unsigned int i;
for (i = 0; i < rule->selectors; i++)
dump_selector(&rule->selector[i]);
css_dump_style(rule->style);
}
void css_dump_stylesheet(const struct css_stylesheet * stylesheet)
{
unsigned int i;
for (i = 0; i < HASH_SIZE; i++) {
struct rule * rule;
fprintf(stderr, "hash %i:\n", i);
for (rule = stylesheet->hash[i]; rule != 0; rule = rule->next)
dump_rule(rule);
}
}
/**
* cascade styles
*/
void css_cascade(struct css_style * const style, const struct css_style * const apply)
{
float f;
if (apply->background_color != CSS_COLOR_INHERIT)
style->background_color = apply->background_color;
if (apply->clear != CSS_CLEAR_INHERIT)
style->clear = apply->clear;
if (apply->color != CSS_COLOR_INHERIT)
style->color = apply->color;
if (apply->display != CSS_DISPLAY_INHERIT)
style->display = apply->display;
if (apply->float_ != CSS_FLOAT_INHERIT)
style->float_ = apply->float_;
if (apply->height.height != CSS_HEIGHT_INHERIT)
style->height = apply->height;
if (apply->text_align != CSS_TEXT_ALIGN_INHERIT)
style->text_align = apply->text_align;
if (apply->width.width != CSS_WIDTH_INHERIT)
style->width = apply->width;
if (apply->font_weight != CSS_FONT_WEIGHT_INHERIT)
style->font_weight = apply->font_weight;
if (apply->font_style != CSS_FONT_STYLE_INHERIT)
style->font_style = apply->font_style;
/* font-size */
f = apply->font_size.value.percent / 100;
switch (apply->font_size.size) {
case CSS_FONT_SIZE_ABSOLUTE:
style->font_size = apply->font_size;
break;
case CSS_FONT_SIZE_LENGTH:
switch (apply->font_size.value.length.unit) {
case CSS_UNIT_EM:
f = apply->font_size.value.length.value;
break;
case CSS_UNIT_EX:
f = apply->font_size.value.length.value * 0.6 /*?*/;
break;
default:
style->font_size = apply->font_size;
}
if ((apply->font_size.value.length.unit != CSS_UNIT_EM) &&
(apply->font_size.value.length.unit != CSS_UNIT_EX))
break;
/* drop through if EM or EX */
case CSS_FONT_SIZE_PERCENT:
switch (style->font_size.size) {
case CSS_FONT_SIZE_ABSOLUTE:
style->font_size.value.absolute *= f;
break;
case CSS_FONT_SIZE_LENGTH:
style->font_size.value.length.value *= f;
break;
default:
die("attempting percentage of unknown font-size");
}
break;
case CSS_FONT_SIZE_INHERIT:
default: /* leave unchanged */
break;
}
}
/**
* testing
*/
/*
int main(int argv, char *argc[])
{
int i;
struct rule * r;
struct css_stylesheet * s;
struct css_selector sel = { "h1", 0, 0 };
struct css_selector con[] = {{ "html", 0, 0 }, {"body", 0, 0}, {"h1", "foo", 0}, {"b", 0, "bar"}};
struct css_style * style = xcalloc(1, sizeof(struct css_style));
s = css_new_stylesheet();
css_parse_stylesheet(s, argc[1]);
css_dump_stylesheet(s);
r->selectors = 1;
css_stylesheet_add_rule(s, r);
puts("********** finding h1:");
r = find_rule(s, &sel, 1);
if (r)
dump_rule(r);
else
puts("not found");
puts("********** finding html body h1.foo b#bar:");
for (i = 1; i <= sizeof(con) / sizeof(con[0]); i++) {
css_get_style(s, con, i, style);
css_dump_style(style);
}
fprintf(stderr, "%x %x\n", r, r2);
struct css_style *s;
struct css_selector *sel;
s = parse_property_list(argc[1]);
css_dump_style(s);
for (i = 2; i < argv; i++) {
css_cascade(s, parse_property_list(argc[i]));
css_dump_style(s);
}*/
/* for (i = 1; i < argv; i++) {
sel = parse_selector(argc[i]);
css_dump_selector(sel);
puts("");
}*/
/*
return 0;
}
*/
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